My electrician is busy elsewhere so I am running the boiler in manual
mode.
It has crossed my mind to wonder about the impact of no overrun
facility. I suppose it would be easy to cycle the water temperature
setting to something lower than the current 50 deg. C and then switch
off.
I am not noticing any *kettling* or other noises.

Any thoughts?
--
Tim Lamb

On Saturday, 31 March 2018 14:47:18 UTC+1, Tim Lamb wrote:
My electrician is busy elsewhere so I am running the boiler in manual
mode.
It has crossed my mind to wonder about the impact of no overrun
facility. I suppose it would be easy to cycle the water temperature
setting to something lower than the current 50 deg. C and then switch
off.
I am not noticing any *kettling* or other noises.

Any thoughts?

If there's no kettling there's no problem. If you turned the boiler stat up or the pump down kettling might occur. You're just not getting the last bit of heat out of the HE by not overrunning. Though why overrun times are routinely set to minutes I don't know.


NT

On 31/03/2018 14:47, Tim Lamb wrote:
My electrician is busy elsewhere so I am running the boiler in manual mode.
It has crossed my mind to wonder about the impact of no overrun
facility. I suppose it would be easy to cycle the water temperature
setting to something lower than the current 50 deg. C and then switch off.
I am not noticing any *kettling* or other noises.

Any thoughts?

The problem would only occur for around 15 seconds at the point where
the boiler burner and the pump both stop at the same time and the latent
heat in the heat exchanger is transferred to the water in the boiler,
which is no longer circulating.

If the boiler burner isn't actually fired up at the time the pump stops
then you will not see a problem.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

In message , alan_m
writes
On 31/03/2018 14:47, Tim Lamb wrote:
My electrician is busy elsewhere so I am running the boiler in manual mode.
It has crossed my mind to wonder about the impact of no overrun
facility. I suppose it would be easy to cycle the water temperature
setting to something lower than the current 50 deg. C and then switch off.
I am not noticing any *kettling* or other noises.
Any thoughts?

The problem would only occur for around 15 seconds at the point where
the boiler burner and the pump both stop at the same time and the
latent heat in the heat exchanger is transferred to the water in the
boiler, which is no longer circulating.

Hmm.. The current control is by the boiler on/off button. AFAIK the
internal pump and burner stop instantly. Usually the boiler has
modulated the burner to a low flame by then.

If the boiler burner isn't actually fired up at the time the pump stops
then you will not see a problem.

The manifold pumps keep running but I don't think they contribute to
boiler flow and return.

I'll start winding the temperature down before switch off as this is
going on for a week or so yet.


--
Tim Lamb